Neomi Rao, the Trump administration’s regulatory “czar,” may soon have a new job. On Tuesday, she was nominated to fill the vacant seat on the D.C. Circuit Court of Appeals left by now-Supreme Court Justice Brett Kavanaugh.

Rao is a good choice for the D.C. Circuit, considered the second-most important court in the land. Her nomination, however, leaves a hole in the administration’s regulatory reform efforts.

Since last year, Rao has served as head of the White House Office of Information and Regulatory Affairs. Often called the most important federal agency no one has heard of, it is tasked with reviewing new federal rules to ensure that they are necessary and consistent with the president’s policies.

Since last year, as the agency’s administrator, Rao has spearheaded efforts to reduce the burden of red tape on Americans. In a report released last month, Rao trumpeted the administration’s successes in that struggle.

Her clearest success was in reducing the number of new regulatory burdens being imposed on American consumers each year. The number of significant new rules coming out of the administration is now lower than at any time since the beginning of the George W. Bush administration.

Rao also worked to roll back existing regulations, with the goal of not just limiting, but actually reducing the burden on Americans. Despite her best efforts, however, less than $1.6 billion in annual costs have been taken from their shoulders. And achieving such rollbacks will only get harder in the future.

The “deregulation” achieved thus far has largely been simply undoing the out-of-control regulatory excesses of the Obama years, which still is costing Americans over $120 billion annually. But many of the costliest targets among the Obama rules have already been challenged, if not always successfully repealed. And addressing pre-Obama regulations will be an even more difficult task, as businesses and consumers tend to be less eager to repeal the regulatory devils they know.

Moreover, there are worrying signs that the Trump administration may soon find itself fighting its own regulators. In a worrisome number of situations, Trump administration policymakers—and even the president himself—have expressed support for new regulatory schemes.

Leading the pack are potential limits on the activity of leading tech firms, including Amazon and Google. The administration also has expressed support for regulation of prescription drug prices and is moving forward with regulation of smokeless tobacco, among other things.

The Office of Information and Regulatory Affairs, fortunately, does not fight the battle against overregulation alone. Policymakers in each regulatory agency are the first line of defense against excessive red tape. And some of the most successful foes of overregulation—including Federal Communications Commission Chairman Ajit Pai—operate independently (and quite successfully) outside of the Office of Information and Regulatory Affairs’ oversight.

Given the steep challenges the Trump administration faces in limiting the regulatory burden shouldered by American consumers, President Donald Trump must move quickly to appoint a new administrator for the agency.

The new regulation czar should be assisted by a beefed up staff of experts to enable the agency—which now numbers only about 50 professional staffers—to better stand toe-to-toe against proponents of regulation.

Congress must also step up to the plate. Specifically, legislation to require congressional approval of all new major rules—known as the REINS (Regulations From the Executive In Need of Scrutiny) Act—has long been pending on Capitol Hill. Now is the time to pass it.

With Democrats taking control of Congress, support for this proposal could actually strengthen, as the new House majority viewed REINS—quite properly—as a necessary check on executive power, enabling Congress to better exercise its vital oversight role.

Rao put the Trump administration firmly on the road to containing and even reducing regulatory burdens. But the work has only just begun. The president should quickly appoint a successor, while providing the Office of Information and Regulatory Affairs with the resources—and Congress assume the authority necessary—to meet the outsized challenges it faces.